This invention relates to an ink jet container or cassette as used in an ink jet printer; and more particularly to an apparatus and method for reducing the introduction of air into the system. Specifically, the invention relates to an improved seal for an ink jet container using a compressive linear seal. It will be appreciated, however, that the invention may find application in related environments and applications that encounter the same issues.
It is generally known in the art to form a container housing or body having one or more cavities or chambers that hold a predetermined supply of ink. For example, a single color of ink may be provided in a single chamber container. Alternatively, multiple chambers may be provided, for example, each holding a different color ink stored therein for selective use in a color printer. It is also generally known to provide an ink absorbing member such as a reticulated polyethylene or melamine foam that fits within the chamber(s). In some arrangements, the ink absorbing member fills the substantial entirety of the chamber, while in other instances a portion of the ink supply is free ink and the remainder is stored in the ink absorbing member. In still other instances, all of the ink is stored as free ink in the container. One or more outlet ports communicate with the respective one or more chambers through outlet passages. The outlet passage proceeds through a first or bottom wall of the housing. A supply needle from an associated printer extends through the outlet port and thus conveys ink from the housing to a recording head or printhead.
Print quality can be adversely affected by the introduction of air into the ink chamber or outlet passage. Thus, manufacturers of ink containers are careful in the design and assembly, i.e., filling, to limit the potential for air introduction into the system. One area of potential air introduction is through a seal member such as a grommet or septum that normally closes the outlet port. Seal members as used in commercially available containers are typically made from a porous material that allows permeation of both air and water. The entry of air through the seal member can dramatically affect performance of the printer, allowing air bubbles to form in the outlet port thus creating print voids or ink starvation problems. Existing seals seal using an external ring that acts like an o-ring. However, the o-ring may be difficult to install and may leak since the bore of the outlet port may not be round or there are variations in the geometry of the outlet port.
Another problem that occurs is that the chimney of the ink container is molded and does not always have a smooth base on the internal diameter of the chimney due to factors such as material shrinkage during the molding process. As a result, a proper interference fit between the outer diameter of a seal disk and the internal diameter of the chimney bore is not achieved.
Accordingly, there exists a need for providing a sealing disk which is compressed upon insertion into a bore of an outlet port of an inkjet container thus limiting the potential for air to enter the container through the outlet port.